Begging your pardon, but I don't think so. I believe the brain lives on after the blood stops flowing for some time. Maybe those choosing shooting vs the sleep-to-death don't realize that.
So shoot 'em in the brain.
Utah firing squads use .30-30 rifles. I would think the impact of several of these soft point bullets slamming into the heart at close range would instantly shut down consciousness due to hydrostatic shock.
Whatever, doesn’t matter. It’s straightforward and effective 100% of the time.